The present invention relates to an intelligent optical disk drive control method for rapidly and accurately controlling the movement of an optical pick-up head of an optical disk drive system. The term, optical disk means a device which utilizes the optical method to read data from the disk.
The hardware structure of a conventional optical disk drive, as shown in FIG. 1, comprises at least: a disk 10, a spindle motor 11, a base plate 12, an optical pick-up head 13 which includes an optical system and a lens actuator, and a sled motor 14 adapted for driving the optical pick-up head 13 for long tracking. The optical system comprises at least a focus lens adapted to focus a laser light onto the disk. The lens actuator comprises a coil adapted for driving the focus lens for tracking and short seeking. The aforesaid hardware devices are controlled by the following servo control systems:
1. Focusing Servo Control: for controlling the movement of a focusing actuator which is equipped with the aforesaid focusing lens, permitting laser light which passes through the focusing lens to be focused onto the disk 10. PA0 2. Sled Servo Control: for moving the optical pick-up head 13 to the object track or its nearby area at a high speed when accessing data. PA0 3. Fine Seeking, Tracking Servo Control: for matching with the sled servo control to control the coil in driving the focusing lens for a fine movement, enabling the optical pick-up head to follow a certain track in the disk 10, so that tracking servo control can be performed to achieve the action of tracking; fine seeking servo control is for track jumping control, and track jumping is one track per each jump. PA0 4. Spindle Servo Control: for controlling the spindle motor 11 to turn the disk 10, causing the optical pick-up head to pick up the data continuously from the disk 10 along a fixed track. PA0 1. turning the disk 10; PA0 2. projecting a laser beam onto the disk 10; PA0 3. focusing the laser beam; PA0 4. tracking - - - turning on the lens actuator to drive the object lens, enabling the laser beam to follow a certain data track; PA0 5. picking up track number - - - reading out the existing track number so as to know the existing track position; PA0 6. sled - - - turning on the sled motor 14 to move the optical pick-up head 13 from the existing track to a nearby area around the object track; PA0 7. tracking; PA0 8. picking up track number - - - reading out the existing track number so as to know the difference between the existing track and the object track; PA0 9. short seeking - - - fine adjusting the coil to move the object lens, enabling the laser beam to be focused onto the object track; PA0 10. tracking; PA0 11. accessing data.
The data access procedure of an optical disk drive is outlined hereinafter with reference to FIG. 2.
The access time of an optical disk drive means the total time used in the aforesaid (6) to (11) six actions. Normally, the time for sled is the longest. Therefore, the servo control of the sled motor 14 has a great concern with the access time. The present invention is achieved to improve the servo control of the sled motor 14, so as to reduce the consumption of the access time.
Using a PID (proportional integrated differentiation) control method to control the servo control of the sled motor of an optical disk drive has been well known. However, the control system parameter of the PID control method tends to cause a floating change when the optical disk drive bears a heavy disk, gaps occur in the transmission mechanism, mechanical parts are aged, or the friction force is changed. Therefore, this conventional optical disk drive control method cannot fit the changes of the control system parameter, and the optical pick-up head positioning time will be increased.